Characterization of Large Brain Metastases with 18F-Fluciclovine PET/CT Treated with Staged Stereotactic Radiosurgery (SSRS): Phase 1 Proof-of-Concept Interim Analysis

PURPOSE/OBJECTIVE(S)

Single-session stereotactic radiosurgery (SRS) for large brain metastases (>2cm) results in modest local control. Temporally staged SRS (SSRS), whereby 2 stages of SRS are delivered over a time interval of several weeks, is a novel strategy associated with improved control rates and acceptable radiation necrosis rates. Biomarkers for response are lacking. Here, we report interim results of a phase 1, proof-of-concept study (NCT04689048) to assess the potential clinical utility of amino acid radiotracer 18F-fluciclovine PET/CT as a functional integral biomarker for patients with large brain metastases treated with SSRS.

MATERIALS/METHODS

Patients with previously untreated large brain metastases (≥1 lesion; >2cm) underwent a baseline (pre-treatment) 18F-fluciclovine PET/CT and contrast-enhanced treatment planning brain MRI immediately before first SSRS (15 Gy), an interim PET/CT + MRI (4 weeks after the 1st SSRS, immediately prior the 2nd SSRS [15 Gy]), and post-treatment PET/CT + MRI (8 weeks after 2nd SSRS). This interim analysis reviewed the imaging characteristics from static PET images acquired 10-25 minutes after 18F-fluciclovine injection, for the first 7 enrolled patients who completed baseline imaging and 5 who completed the entire treatment course.

RESULTS

Seven patients completed baseline imaging and were treated with SSRS for 9 protocol-eligible target lesions, and an additional 25 bystander lesions were treated with SRS. The median age was 72 years and 57% were female. All lesions > 5 mm exhibited baseline increased 18F-fluciclovine uptake compared to the normal contralateral brain. The median baseline target lesion diameters and volumes were 2.16 cm (1.76-3.22 cm) and 4.71cc (2.24-10.21 cc). The median baseline SUVmax, SUVpeak, and SUVmean values were 5.78 (2.16-8.79), 3.33 (0.5-2.72), and 1.75 (1.22-5.16), respectively. The median relative reduction in diameter and volume were both 2% (-13% to 23% and -30% to 60%, respectively) at the interim scans, and at the first follow-up were 30% (-0.2% to 44%) and 43% (-13% to 94%), respectively. Corresponding median relative reduction values for SUVmax, SUVpeak, and SUVmean at interim scans were 20% (-174%-73%), 9% (-99% to 75%), and 14% (-36% to 69%), and at first follow-up 59% (21% to 87%), 41% (-11% to 86%), and 21% (-44% to 79%), respectively. Bystander lesions (< 2 cm) treated with SRS had a median baseline lesion diameter and volume of 0.5 cm (Range: 0.20-1.64 cm) and 0.06 cc (Range: 0.01-1.94 cc). Corresponding median reductions for SUVmax were 5% at interim and 63% at follow-up scans.

CONCLUSION

This proof-of-concept interim study reports baseline 18F-fluciclovine metrics for patients with brain metastases of varying lesion diameters and volumes. Target lesions appear to demonstrate interval reduction in PET metrics after SSRS, more than dimensional measurements alone.

A63 TRENDS AND OUTCOMES OF LIVER DISEASE HOSPITALIZATIONS DURING THE CORONAVIRUS PANDEMIC IN THE UNITED STATES: A NATIONWIDE POPULATION-LEVEL ANALYSIS

Background

The impact of the Coronavirus disease-2019 (COVID-19) pandemic on patients with liver disease is not well described at the population level in the United States.

Purpose

We used the largest, nationwide inpatient dataset to describe inpatient liver disease outcomes in the United States during the first year of the pandemic (2020) using 2018 and 2019 as comparator years.

Method

Using the National Inpatient Sample (2018-2020), we explored year-to-year and 2020 month-to-month trends in hospitalizations, length of stay, and inpatient mortality for liver-related indications including compensated cirrhosis, decompensated cirrhosis, alcohol-associated liver disease (ALD), alcohol-associated hepatitis (AH), hepatocellular carcinoma (HCC), and variceal upper gastrointestinal bleeding (VUGIB) using regression modeling. We also looked at the impact of the COVID-19 pandemic on liver transplantation rates. A p-value <0.05 was considered statistically significant.

Result(s)

Hospitalizations for both compensated and decompensated cirrhosis decreased in 2020 compared to 2019 (relative change [RC] of 1.5%, p <0.001, Table 1). Interestingly, hospitalizations for ALD and AH increased in 2020 compared to pre-pandemic years (ALD RC=15.5% and AH RC 17.0%; p<0.001). Despite the decrease in cirrhosis hospitalizations in 2020, all-cause inpatient mortality among patients with compensated cirrhosis increased from 30,135 in 2019 to 35,220 in 2020 (p<0.001) and from 22,850 in 2019 to 26,390 in 2020 among patients with decompensated cirrhosis (p<0.001). This was accompanied by a 27.8% increase in mortality for ALD (p=0.004) in comparison to pre-pandemic years. Corresponding to the peaks of the pandemic, we observed the fewest cirrhosis hospitalizations in April and December 2020 (Table 2), however, these months had the highest observed mortality rates (p-trend ≤ 0.004). Reassuringly, liver transplantation rates were not significantly impacted by the COVID-19 pandemic (p=0.51).

Image

Conclusion(s)

Cirrhosis hospitalizations, in general, decreased in 2020 compared to pre-pandemic years but were associated with higher all-cause mortality rates particularly in the peak months of the COVID-19 pandemic (April and December 2020) possibly reflecting COVID-19 specific mortality. Alcoholic liver disease admissions also increased during the pandemic while liver transplantation rates were not significant impacted.

Please acknowledge all funding agencies by checking the applicable boxes below

None

Disclosure of Interest

None Declared

P3654Location of the coronary origins in transposition patients following anatomical repair: Implications for invasive coronary angiography and intervention

Background

Surgical repair of transposition of the great arteries (TGA) is most commonly via the arterial switch operation (ASO). This involves translocation of the aorta and pulmonary trunk, typically with anastomosis of the branch pulmonary arteries anteriorly (LeCompte manoeuvre) and re-implantation of the coronary arteries onto the posterior neo-aorta. As such, the position of the coronary ostia may differ from their expected locations.

Purpose

To use ECG-gated CT angiography to describe the anatomic position of coronary ostia in post-switch TGA patients guiding potential catheter interventions in this population.

Methods

All post ASO patients who underwent CT imaging between 2008–2018 were identified. Patients with complex anatomy such as double outlet right ventricle were excluded. The positions of the coronary ostia were measured in degrees from vertical on a double-oblique reconstruction in the aortic valve plane. Ostium positions were compared to those of patients with no congenital heart disease via Watson's two-sample test of homogeneity for circular data. Angular dispersion was compared between groups via the Wallraff test. P<0.05 indicated statistical significance.

Results

Of 206 adult patients with TGA and ASO followed in our adult congenital heart disease centre, 38 (18.4%) had CT imaging available for analysis during the study period (mean age 24±6.8, 75% male).

The control group consisted of 15 patients investigated for chest pain (mean age 54±15.1, 73% male). In the control group, the right and left coronary ostia arose at a mean angle of −19 and +125 degrees from vertical (figure 1a). This was significantly different to the mean ASO coronary ostia clustered at mean angles of −70 and +29 degrees from vertical (Watson p<0.001) (figure 1b, with stenosis at the left coronary anastomosis).

There was no significant difference in spread of left ostia (Rho 0.9 vs 0.99, p=0.12), but right ostia were significantly more variable in ASO patients than controls (0.71 vs 0.96, p=0.003).

Figure 1

Conclusions

Coronary ostial positions in the neo-aorta of post-ASO patients differ significantly from those of normal controls, with considerable variability, especially in right coronary position. CT can demonstrate coronary ostia in 3D space and derive appropriate tube angles to guide catheterisation in post-operative congenital cardiac patients, optimise catheter selection, reduce catheterisation tome, radiation and contrast dose.

'Porcelain aorta': a proposed definition and classification of ascending aortic calcification

Introduction

‘Porcelain aorta’ is listed in the second consensus document of the Valve Academic Research Consortium as a risk factor in aortic valve replacement. However, the extent of circumferential involvement is poorly defined with great variability in reported incidence. We present a simple, reproducible classification to describe the extent of aortic calcification and thus appropriately define ‘porcelain aorta’, aiding clinical decision-making and registry data collection.

Methods

175 consecutive CT aortograms were reviewed. The aorta was divided into three sections, and each section divided into quadrants. These were individually scored using a 5-point scale (0—no calcification, 5—complete contiguous calcification).

Results for each quadrant were summated for each segment to provide an indication of the distribution of calcification.

Results

Only one patient (0.6%) had a ‘true’ porcelain aorta, defined as contiguous calcification across all quadrants at any aortic level. Intraobserver and interobserver variation was excellent for the ascending aorta (K=0.85–0.88 and 0.81–0.96, respectively) while the interobserver variation in the transverse arch was good at 0.75.

Conclusions

Our data suggest the incidence of ‘true’ porcelain aorta may be significantly lower than reported in the literature. The predominance of calcification within the anterior wall of the proximal ascending aorta and the superior wall of the transverse arch may be clinically important. Application of this quick, simple and reproducible grading system, with no requirement for advanced software, may provide a tool to support accurate assessment of focal aortic calcification and its relationship to subsequent procedural risk.

An unusual case of false-positive coronary artery calcium score

False-negative results of coronary artery calcium score (CACS) are common due to small calcified lesions being missed using a 3-mm slice thickness, a threshold of 130 Hounsfield units (HU) and a minimum area of 1 mm² for defining a calcified plaque. In contrast, false-positive results of CACS, as verified by a lack of coronary artery calcifications in computed tomography coronary angiogram (CTCA), are extremely uncommon. We present a patient with a false-positive coronary calcium score who had normal coronary arteries in CTCA.

An unusual case of ventricular ectopy in a military pilot

BACKGROUND

Congenital left ventricular diverticula are an uncommon cardiac malformation. Although they may be asymptomatic, their presence is important to note as they are associated with systemic embolization of mural thrombus, valvular regurgitation, heart failure, focal ventricular arrhythmias, and sudden death.

CASE REPORT

We describe a case of an asymptomatic pilot with a significant burden of ventricular ectopy. The diagnosis of a large left ventricular diverticulum was made by cardiac CT and confirmed by cardiac magnetic resonance imaging. No specific treatment was warranted; however, regular on-going follow up was required.

DISCUSSION

It is important to seek out a structural cause for frequent ventricular ectopy even in the absence of symptoms. Transthoracic echocardiography is not always able to delineate the entire left ventricular cavity and other imaging modalities such as ECG-gated cardiac CT or gated MRI may need to be used in conjunction to permit assessment for the presence of structural heart disease in the whole heart. Aircrew with a high burden of ectopy require regular follow-up for complications such as more malignant dysrhythmias or LV impairment. In some cases, pharmacological or even surgical treatment is warranted, which may have a significant bearing for the future licensing of aircrew.

Personalised external aortic root support (PEARS) in Marfan syndrome: analysis of 1-9 year outcomes by intention-to-treat in a cohort of the first 30 consecutive patients to receive a novel tissue and valve-conserving procedure, compared with the published results of aortic root replacement

OBJECTIVE

Among people with Marfan syndrome who have a typical aortic root aneurysm, dissection is a characteristic cause of premature death. To pre-empt Type A dissection, composite root replacement with a mechanical valve became the standard of care in the 1980s and 1990s. This is being superseded by valve-sparing aortic root replacement to avoid lifelong anticoagulation. In 2004, a total root and valve-sparing procedure, personalised external aortic support, was introduced. We report here results among the first 30 recipients.

METHODS

From cross-sectional digital images, the patient's own aorta is modelled by computer aided design and a replica is made in thermoplastic by rapid prototyping. On this, a personalised support of a macroporous polymer mesh is manufactured. The mesh is positioned around the aorta, closely applied from the aortoventricular junction to beyond the brachiocephalic artery. The operation is performed with a beating heart and usually without cardiopulmonary bypass.

RESULTS

Between 2004 and 2011, 30 patients, median age 28 years (IQR 20-44) had this operation and have been prospectively followed for 1.4-8.8 years by February 2013. During a total of 133 patient-years there were no deaths or cerebrovascular, aortic or valve-related events. These early outcomes are better than published results for the more radical extirpative root replacement operations.

CONCLUSIONS

The aortic valve, the root architecture, and the blood/endothelia interface are conserved. The perioperative burden is less and there has been freedom from aortic and valvular events. A prospective comparative study is planned.

Catastrophic antiphospholipid syndrome in childhood: presentation with an inferior caval vein mass

Venous thromboembolism remains one of the important causes of pulmonary hypertension in children. The causes of venous thromboembolism are varied and include antiphospholipid antibody syndrome (APS). Catastrophic APS (CAPS) is a severe variant of APS characterised by disseminated thrombosis and microangiopathy resulting in multiorgan failure. CAPS can occur independently (primary APS) but mainly occurs in association with systemic lupus erythematosus including the paediatric population. We report a young girl with primary CAPS who presented with pulmonary hypertension and an inferior vena cava mass masquerading as a tumour.

Large aneurysm of left coronary sinus of Valsalva presenting with effort-related ventricular fibrillation

Sinus of Valsalva aneurysms are very rare and are often asymptomatic. Clinical manifestations depend on associated complications, most commonly rupture or dissection. We describe the unusual case of a 46-year old presenting with exercise-induced ventricular fibrillation due to extrinsic compression of the left coronary artery. We also describe the surgical correction by valve-sparing aortic root replacement.

Multimodality imaging in transcatheter aortic valve implantation and post-procedural aortic regurgitation: comparison among cardiovascular magnetic resonance, cardiac computed tomography, and echocardiography

OBJECTIVES

The purpose of this study was to determine imaging predictors of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) and the agreement and reproducibility of cardiovascular magnetic resonance (CMR), cardiac computed tomography (CCT), and transthoracic echocardiography (TTE) in aortic root assessment.

BACKGROUND

The optimal imaging strategy for planning TAVI is unclear with a paucity of comparative multimodality imaging data. The association between aortic root morphology and outcomes after TAVI also remains incompletely understood.

METHODS

A total of 202 consecutive patients assessed by CMR, CCT, and TTE for TAVI were studied. Agreement and variability among and within imaging modalities was assessed by Bland-Altman analysis. Postoperative AR was assessed by TTE.

RESULTS

Of the 202 patients undergoing TAVI assessment with both CMR and TTE, 133 also underwent CCT. Close agreement was observed between CMR and CCT in dimensions of the aortic annulus (bias, -0.4 mm; 95% limits of agreement: -5.7 to 5.0 mm), and similarly for sinus of Valsalva, sinotubular junction, and ascending aortic measures. Agreement between TTE-derived measures and either CMR or CCT was less precise. Intraobserver and interobserver variability were lowest with CMR. The presence and severity of AR after TAVI were associated with larger aortic valve annulus measurements by both CMR (p = 0.03) and CCT (p = 0.04) but not TTE-derived measures (p = 0.10). Neither CCT nor CMR measures of annulus eccentricity, however, predicted AR after TAVI (p = 0.33 and p = 0.78, respectively).

CONCLUSIONS

In patients undergoing imaging assessment for TAVI, the presence and severity of AR after TAVI were associated with larger aortic annulus measurements by both CMR and CCT, but not TTE. Both CMR and CCT provide highly reproducible information in the assessment of patients undergoing TAVI.

Rate of progression and functional significance of aortic root calcification after homograft versus freestyle aortic root replacement

BACKGROUND

Calcification is an important limitation after aortic root replacement. The aims were to compare the long-term degree and rate of calcification of homografts versus Medtronic freestyle aortic roots to determine the functional consequences and predictive factors.

METHODS AND RESULTS

One hundred sixty-six patients were prospectively randomized to undergo homograft versus freestyle total aortic root replacement. Of those, 98 patients underwent a total of 248 electron beam computed tomography studies at 0.5, 1, 1.5, 2, 3, and 8 years. All patients underwent yearly clinical and echocardiographic follow-up. Calcium scores were measured using Agatston scoring. Mixed effects models demonstrate significantly higher calcium scores in homograft roots than freestyle at 1.5 years (P=0.02), 2 years (P=0.02), and 3 years (P=0.01), with a trend at 1 year (P=0.06) and 8 years (P=0.1). Homograft calcification occurs significantly faster than in freestyle prostheses between 6 months and 3 years after surgery (P=0.02). Calcification occurs at a similar rate thereafter up to 8 years (P=0.3). At 8 years, freedom from aortic valve dysfunction was lower in homografts than freestyle roots (P=0.06). Freedom from reoperation was 93+/-4% in the homograft group versus 100+/-0% in the freestyle group at 8 years (P=0.01). On multivariate analysis, redo surgery (P<0.001), smoking (P<0.01), atrial fibrillation (P=0.001), family history of coronary artery disease (P<0.01), and a degenerative etiology (P=0.02) were predictive of higher calcium scores.

CONCLUSIONS

Homograft roots exhibit significantly higher calcium scores than freestyle roots because of faster early calcification.